Mandy Salassi (left) of Baton Rouge, Louisiana talks on her cell phone on Thursday, February 18, 2010, in San Francisco, Calif. State Sen. Mark Leno is introducing a bill designed to give consumers more information about how much radiation their cell phones emit.

Photo: Lea Suzuki, Special To The Chronicle

Mandy Salassi (left) of Baton Rouge, Louisiana talks on her cell...

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State Sen. Mark Leno, D-San Francisco,

Photo: Rich Pedroncelli, Associated Press

State Sen. Mark Leno, D-San Francisco,

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Kim Humphrey (l to r) and Tom Robinson, both of Olympia, Washington, use their cell phones at Market and Powell Streets on Thursday, February 18, 2010, in San Francisco, Calif. State Sen. Mark Leno is introducing a bill designed to give consumers more information about how much radiation their cell phones emit.

Californians may soon easily know how much radiation is being emitted by their cellular phones under legislation introduced at the Capitol on Thursday.

The bill, authored by state Sen. Mark Leno, D-San Francisco, would require manufacturers to print the radiation information on packaging and instruction manuals and for retailers to display that information on the sales floor.

Leno praised the technological advancements of cell phones. But, he said, "they also emit radio frequency radiation that does have human health effects." He called the legislation "a very modest proposal."

There is no scientific proof that cell phones cause cancer or other ailments, according to the Federal Communications Commission, though the federal government is monitoring the results of studies worldwide, according to the commission's Web site.

Leno pointed to studies from around the world that found people who have used cell phones for more than a decade had an increased risk of brain tumors, both malignant and benign, and benign tumors in the salivary glands. He said he believes looking at long-term effects is the most pressing need as cell phones become a ubiquitous accessory for both adults and younger people.

The bill is modeled after legislation under consideration at San Francisco City Hall that would require the radiation numbers to be posted in stores that sell the phones and in a font at least as big as the printed price. The cellular phone industry opposes both proposals.

Radiation levels are regulated by the FCC, which has set maximum radiation emission for cell phones at 1.6 watts per kilogram. The levels vary widely for cell phones and they are available to the public through the FCC Web site, though some information about specific phones is difficult to find through the commission.

The Environmental Working Group, a national nonprofit research and advocacy organization, has published the rates of phones and has a database on its Web site. A Blackberry Storm 9530, for example, emits 0.57 watts per kilogram while a Blackberry Bold 9700 emits 1.55 watts per kilogram. An Apple iPhone 3GS emits 1.19 watts per kilogram.

Renee Sharp, director of the group's California office, said creating the site was tedious and called the FCC's Web site to find the levels "incredibly confusing."

Even with the group's site, though, "the fact is when most people walk into a cell phone store, they're not going to be looking at Web sites. They need information there so they can compare the levels of phones right in front of them," Sharp said.

But the cell phone industry asserts that printing the information, known as the "specific absorption rate," on packaging or posting it in a store is unnecessary and would mislead consumers about the safety of the devices.

"All cell phones sold in the United States must comply with the FCC's limit. According to the FCC, 'any cell phone at or below these SAR levels is a 'safe' phone,' " said John Walls, vice president of public affairs for CTIA-The Wireless Association, in a statement.

Sharp said the FCC's data is "completely out of date." She said she is not suggesting that cell phones cause cancer, "but the evidence suggests that they might."